linux-kernel - [PATCH 3.16 085/254] nl80211: fix nl80211_send

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Date:   Wed, 28 Feb 2018 15:20:18 +0000
From:   Ben Hutchings <ben@...adent.org.uk>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:     akpm@...ux-foundation.org,
        "Johannes Berg" <johannes.berg@...el.com>
Subject: [PATCH 3.16 085/254] nl80211: fix nl80211_send_iface() error paths

3.16.55-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Johannes Berg <johannes.berg@...el.com>

commit 4564b187c16327045d87596e8980c65ba7b84c50 upstream.

Evidently I introduced a locking bug in my change here,
the nla_put_failure sometimes needs to unlock. Fix it.

Fixes: 44905265bc15 ("nl80211: don't expose wdev->ssid for most interfaces")
Signed-off-by: Johannes Berg <johannes.berg@...el.com>
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 net/wireless/nl80211.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -2346,7 +2346,7 @@ static int nl80211_send_iface(struct sk_
 	case NL80211_IFTYPE_AP:
 		if (wdev->ssid_len &&
 		    nla_put(msg, NL80211_ATTR_SSID, wdev->ssid_len, wdev->ssid))
-			goto nla_put_failure;
+			goto nla_put_failure_locked;
 		break;
 	case NL80211_IFTYPE_STATION:
 	case NL80211_IFTYPE_P2P_CLIENT:
@@ -2359,7 +2359,7 @@ static int nl80211_send_iface(struct sk_
 		if (!ssid_ie)
 			break;
 		if (nla_put(msg, NL80211_ATTR_SSID, ssid_ie[1], ssid_ie + 2))
-			goto nla_put_failure;
+			goto nla_put_failure_locked;
 		break;
 		}
 	default:
@@ -2370,6 +2370,8 @@ static int nl80211_send_iface(struct sk_
 
 	return genlmsg_end(msg, hdr);
 
+ nla_put_failure_locked:
+	wdev_unlock(wdev);
  nla_put_failure:
 	genlmsg_cancel(msg, hdr);
 	return -EMSGSIZE;